@Awesome-Tauren
2016-06-13T07:14:14.000000Z
字数 16146
阅读 550
rn
flex是Flexible Box的缩写,意为"弹性布局",用来为盒状模型提供最大的灵活性。采用flex布局的元素,称为flex容器(flex container),简称"容器"。它的所有子元素自动成为容器成员,称为flex项目(flex item),简称"项目"。如下图所示:
容器默认存在两根轴:主轴(main axis)和交叉轴(cross axis)。主轴的开始位置(与边框的交叉点)叫做main start,结束位置叫做main end;交叉轴的开始位置叫做cross start,结束位置叫做cross end。
项目默认沿主轴排列。单个项目占据的主轴空间叫做main size,占据的交叉轴空间叫做cross size。
Flex布局与Android的线性布局(LinearLayout)有点类似,都可以设置布局方向,对齐方式,以及项目的布局占位权重,区别是flex容器中项目分布的总长度超出屏幕宽度,超出的那部分项目不可见,项目不会变形,或者可以设置flexWrap属性,让容器可以分行布局,所有项目都能显示出来。
flex属性声明在:/node_modules/react-native/Libraries/StyleSheet/LayoutPropTypes.js
// https://developer.mozilla.org/en-US/docs/Web/CSS/flex-direction
flexDirection: ReactPropTypes.oneOf([
'row',
'column'
]),
// https://developer.mozilla.org/en-US/docs/Web/CSS/flex-wrap
flexWrap: ReactPropTypes.oneOf([
'wrap',
'nowrap'
]),
// How to align children in the main direction
// https://developer.mozilla.org/en-US/docs/Web/CSS/justify-content
justifyContent: ReactPropTypes.oneOf([
'flex-start',
'flex-end',
'center',
'space-between',
'space-around'
]),
// How to align children in the cross direction
// https://developer.mozilla.org/en-US/docs/Web/CSS/align-items
alignItems: ReactPropTypes.oneOf([
'flex-start',
'flex-end',
'center',
'stretch'
]),
// How to align the element in the cross direction
// https://developer.mozilla.org/en-US/docs/Web/CSS/align-items
alignSelf: ReactPropTypes.oneOf([
'auto',
'flex-start',
'flex-end',
'center',
'stretch'
]),
// https://developer.mozilla.org/en-US/docs/Web/CSS/flex
flex: ReactPropTypes.number,
由上述代码,我们可以看到flex的属性并不多,而且很好记忆,以下将会一一介绍
flex属性可以分为容器属性和项目属性
其中容器属性包括:flexDirection
,justifyContent
,alignItems
,flexWrap
项目属性包括:flex
,alignSelf
以下介绍会使用到一些代码和图片,先定义两个简单组件,方便理解
//定义一个默认半径为20,颜色为#527fe4的圆组件
var Circle = React.createClass({
render : function(){
var size = this.props.size || 20;
var color = this.props.color || '#527fe4';
return <View style={{backgroundColor:color,borderRadius:size/2,height:size,width:size,margin:1}}/>
},
});
//定义一个放置标题和项目的容器,传入的value属性将会是需要介绍的flex属性
var Value = React.createClass({
render : function(){
var value =
<View>
<Text style={styles.valueText}>{this.props.title}</Text>
<View style={[styles.valueContainer,this.props.value]}>
{this.props.children}
</View>
</View>;
return value;
},
});
//定义一个数组放置5个圆
var children = [<Circle/>,<Circle/>,<Circle/>,<Circle/>,<Circle/>];
flexDirection:布局方向,决定主轴的方向,默认值是column
,即纵向布局
值 | 描述 |
---|---|
row | 横向布局,主轴为水平方向 |
column | 纵向布局,主轴为竖直方向 |
row:横向布局
代码:
<Value title='row' value={{flexDirection:'row'}}>
{children}
</Value>
视图:
column:纵向布局
代码:
<Value title='column' value={{flexDirection:'column'}}>
{children}
</Value>
视图:
justifyContent:主轴方向对齐方式,默认值是flex-start
,即主轴的开端
值 | 描述 |
---|---|
flex-start | 主轴开端 |
center | 居中 |
flex-end | 主轴末端 |
space-between | 项目与项目之间插入相等空隙 |
space-around | 项目两旁插入相等空隙 |
flex-start:主轴开端
代码:
<Value title='flex-start' value={{flexDirection:'row', justifyContent:'flex-start'}}>
{children}
</Value>
视图:
center:主轴的中间位置
代码:
<Value title='center' value={{flexDirection:'row',justifyContent:'center'}}>
{children}
</Value>
视图:
flex-end:主轴的末端位置
代码:
<Value title='flex-end' value={{flexDirection:'row',justifyContent:'flex-end'}}>
{children}
</Value>
视图:
space-between:项目与项目之间插入相同距离的空隙
代码:
<Value title='space-between' value={{flexDirection:'row',justifyContent:'space-between'}}>
{children}
</Value>
视图:
space-around:项目两旁插入相同距离的空隙
代码:
<Value title='space-around' value={{flexDirection:'row',justifyContent:'space-around'}}>
{children}
</Value>
视图:
alignItems:交叉轴方向对齐方式,默认值flex-start
,即交叉轴开端
值 | 描述 |
---|---|
flex-start | 交叉轴开端 |
center | 交叉轴居中 |
flex-end | 交叉轴末端 |
flex-start:交叉轴开端
center:交叉轴的中间位置
flex-end:交叉轴的末端位置
flexWrap:包含内容,默认值是nowrap
,不包裹所有内容
值 | 描述 |
---|---|
nowrap | 项目沿主轴方向布局,超出容器长度的部分不可见 |
wrap | 项目沿主轴布局所需长度大于容器总长度时,分行布局,所有项目内容都可见 |
nowrap:不包裹内容
代码:
<Value title='nowrap' value={{flexWrap:'nowrap',flexDirection:'row'}}>
{children}{children}{children}{children}
</Value>
视图::
wrap:包裹内容
代码:
<Value title='wrap' value={{flexWrap:'wrap',flexDirection:'row'}}>
{children}{children}{children}{children}
</Value>
视图:
flex:布局权重
值 | 描述 |
---|---|
>=0 | 项目占位权重,容器包含至少2项目时,项目使用flex属性才有意义 |
1:0:flex=0的项目占用空间仅为内容所需空间,flex=1的项目会占据其余所有空间
代码:
<Value title='1:0' value={{flexDirection:'row'}}>
<Text style={{color:'white',flex:1,textAlign:'center',backgroundColor:'red',fontSize:20,paddingHorizontal:10}}>flex=1</Text>
<Text style={{color:'white',textAlign:'center',backgroundColor:'yellow',fontSize:20,paddingHorizontal:10}}>flex=0</Text>
</Value>
2:1
代码:
<Value title='2:1' value={{flexDirection:'row'}}>
<Text style={{color:'white',flex:2,textAlign:'center',backgroundColor:'blue',fontSize:20}}>flex=2</Text>
<Text style={{color:'white',flex:1,textAlign:'center',backgroundColor:'green',fontSize:20}}>flex=1</Text>
</Value>
1:1:1:1
代码:
<Value title='1:1:1:1' value={{flexDirection:'row'}}>
<Text style={{color:'white',flex:1,textAlign:'center',backgroundColor:'red',fontSize:20}}>flex=1</Text>
<Text style={{color:'white',flex:1,textAlign:'center',backgroundColor:'yellow',fontSize:20}}>flex=1</Text>
<Text style={{color:'white',flex:1,textAlign:'center',backgroundColor:'blue',fontSize:20}}>flex=1</Text>
<Text style={{color:'white',flex:1,textAlign:'center',backgroundColor:'green',fontSize:20}}>flex=1</Text>
</Value>
alignSelf:项目交叉轴方向自身对齐方式
值 | 描述 |
---|---|
flex-start | 开端 |
center | 居中 |
flex-end | 末端 |
代码:
<Value title='alignSelf' value={{flexDirection:'row',height:30,alignItems:'center'}}>
<View style={{alignSelf:'flex-start'}}>
<Circle/>
</View>
<View style={{alignSelf:'flex-end'}}>
<Circle/>
</View>
<View style={{alignSelf:'flex-start'}}>
<Circle/>
</View>
<View style={{alignSelf:'flex-end'}}>
<Circle/>
</View>
<View style={{alignSelf:'flex-start'}}>
<Circle/>
</View>
</Value>
视图:
layout除了flex属性之外,当然还有其他属性,同样声明在:/node_modules/react-native/Libraries/StyleSheet/LayoutPropTypes.js
width: ReactPropTypes.number,
height: ReactPropTypes.number,
top: ReactPropTypes.number,
left: ReactPropTypes.number,
right: ReactPropTypes.number,
bottom: ReactPropTypes.number,
margin: ReactPropTypes.number,
marginVertical: ReactPropTypes.number,
marginHorizontal: ReactPropTypes.number,
marginTop: ReactPropTypes.number,
marginBottom: ReactPropTypes.number,
marginLeft: ReactPropTypes.number,
marginRight: ReactPropTypes.number,
padding: ReactPropTypes.number,
paddingVertical: ReactPropTypes.number,
paddingHorizontal: ReactPropTypes.number,
paddingTop: ReactPropTypes.number,
paddingBottom: ReactPropTypes.number,
paddingLeft: ReactPropTypes.number,
paddingRight: ReactPropTypes.number,
borderWidth: ReactPropTypes.number,
borderTopWidth: ReactPropTypes.number,
borderRightWidth: ReactPropTypes.number,
borderBottomWidth: ReactPropTypes.number,
borderLeftWidth: ReactPropTypes.number,
position: ReactPropTypes.oneOf([
'absolute',
'relative'
]),
属性 | 类型 | 描述 |
---|---|---|
width | number | 容器或者项目的宽度 |
height | number | 容器或者项目的高度 |
top,bottom,left,right | number | 在父容器的上下左右偏移量 |
margin | number | 留边,留边的空间不属于容器或者项目自身空间 |
marginHorizontal | number | 水平方向留边 |
marginVertical | number | 垂直方向留边 |
padding | number | 填充,填充的空间输入容器或者项目自身空间 |
paddingHorizontal | number | 水平方向填充 |
paddingVertical | number | 垂直方向填充 |
borderWidth | number | 边界宽度 |
position | enum | 位置方式:absolute与relative |
position:默认值为relative
值 | 描述 |
---|---|
absolute | 绝对布局 |
relative | 相对布局 |
react的默认位置方式是relative,项目是一个接一个排列下去的,absolute为绝对布局,一般会与left和top属性一起使用。有时候我们需要实现某些项目重叠起来,absolute属性就能发挥作用了,例如下图:
react的基本组件暂时不支持以图片作为背景,所以这里的的转入
是一个文本组件,而红色的圆形是一个图片组件,在IOS里面组件也可以作为容器,图片可以正常显示,但是在Android里面,可能存在些问题,如果使用组件作为容器都会出现图片变得好奇怪,所以就可以absoulte来解决问题了。代码如下:
<View style={{width:80,height:80,alignItems:'center',justifyContent:'center'}}>
<Image style={{position:'absolute',left:0,top:0,resizeMode:'contain',width:80,height:80}} source={require('image!finance_usercenter_ic_into')}/>
<Text style={{width:80,textAlign:'center',color:'white',fontSize:16}}>转入</Text>
</View>
这里的View跟Android的View有点不一样,View是可以作为容器也可以作为项目,View作为容器还有其他很多属性,例如backgroundColor,borderWidth,borderColor,opacity等等,这里不一一介绍。
react native的宽高是不需要带单位的,那些width
,height
,padding
,margin
的赋值都直接是数字的,当你设定width:10
,在IOS的话就是设置了10pt宽度,而在Android上面是10dp,在做项目时,辛勤的美工会帮我们标出所有UI控件的宽,高,边距等等,他们用的单位也是dp,所以赋值style中宽高时,直接填入数字即可。
先上预览图:
TitleBar
'use strict'
var React = require('react-native');
var {
Image,
Text,
TouchableWithoutFeedback,
StyleSheet,
View,
} = React;
var TitleBar = React.createClass({
getInitialState: function()
{
return ({
loginState:0,
});
},
render: function(){
return(
<View style={styles.container}>
<Image style={styles.icon}
source={require('image!ic_low_login_head')}/>
<Text style={styles.title}>{this.props.title}</Text>
<Image style={styles.icon} source={require('image!ic_low_login_news')}/>
</View>
);
},
});
var styles = StyleSheet.create({
container:{
flexDirection:'row',
paddingLeft:16,
paddingTop:8,
paddingRight:16,
paddingBottom:8,
height:56,
alignItems:'center',
backgroundColor:'#63534e'
},
icon:{
resizeMode:'cover',
width:30,
height:30,
},
title:{
flex:1,
marginLeft:10,
textAlign:'left',
color:'white',
fontSize:15,
},
});
module.exports = TitleBar;
Header
var Header = React.createClass({
getInitialState:function(){
return {
data:{
total:2345.67,
increasement:0.00,
},
};
},
render: function(){
var data = this.state.data;
var total = data.total;
var increasement = data.increasement;
var header =
<View style={{flexDirection:'row', alignItems:'center', paddingTop:17,paddingBottom:10,paddingRight:17,backgroundColor:'#63534e'}}>
<View style={{flex:1, marginLeft:16}}>
<Text style={{color:'#9a8f8d',fontSize:13,}}>活期余额(元)</Text>
<View style={{flexDirection:'row', alignItems:'flex-start', marginTop:5}}>
<Text style={{color:'#ffe7bc',fontSize:32}}>{parseInt(total)+'.'}</Text>
<Text style={{color:'#ffe7bc',fontSize:18, marginTop:5}}>{total*100%100}</Text>
</View>
<Text style={{color:'#9a8f8d',fontSize:10,marginTop:5}}>昨日+{increasement}</Text>
</View>
<View style={{width:80,height:80,alignItems:'center',justifyContent:'center'}}>
<Image style={{position:'absolute',left:0,top:0,resizeMode:'contain',width:80,height:80}} source={require('image!finance_usercenter_ic_into')}/>
<Text style={{width:80,textAlign:'center',color:'white',fontSize:16}}>转入</Text>
</View>
<View style={{width:80,height:80,alignItems:'center',justifyContent:'center'}}>
<Image style={{position:'absolute',left:0,top:0,resizeMode:'contain',width:80,height:80}} source={require('image!finance_usercenter_ic_out')}/>
<Text style={{width:80,textAlign:'center',color:'white',fontSize:16}}>转出</Text>
</View>
</View>;
return header;
},
});
Insurance
var Insurance = React.createClass({
fetchData:function(){
var url = 'http://202.69.27.140/btoa/portal/financial/financialList';
fetch(url).then((response) => response.json()).then((responseData) => {
var categoryList = responseData.data.categoryList;
for(var i=0;i<categoryList.length;i++){
var categoryItem = categoryList[i];
if(categoryItem.category==='insure'){
this.setState({
data: this.state.data.cloneWithRows(categoryItem.productList),
loaded: true,
expanded: true,
});
}
}
}).done();
},
componentDidMount:function(){
this.fetchData();
},
getInitialState:function(){
return {
data:new ListView.DataSource({
rowHasChanged:(r1,r2)=>r1!==r2,
}),
loaded:false,
expanded:false,
};
},
renderRow:function(item)
{
var price = (item.productTypeID===30014)?'8.5折起':item.minPremium+'~'+item.maxPremium+'元';
var ensure = (item.productTypeID===30014)?'':parseFloat(item.minEnsure/10000)+'~'+parseFloat(item.maxEnsure/10000)+'万';
var itemView =
<View style={{paddingVertical:15,paddingLeft:17,borderBottomWidth:0.5,borderBottomColor:'#dddddd',backgroundColor:'white'}}>
<Text style={{color:'#6a534f',fontSize:18}}>{item.productName}</Text>
<View style={{flexDirection:'row',}}>
<Text style={{flex:1,color:'#fc7200',fontSize:24}}>{price}</Text>
<Text style={{flex:1,color:'#6a534f',fontSize:24}}>{ensure}</Text>
</View>
<Text style={{color:'#a19796',fontSize:12}}>保费</Text>
</View>;
return itemView;
},
render:function(){
var listView = <ListView dataSource={this.state.data} renderRow={this.renderRow}/>;
var moreView = <TouchableWithoutFeedback style={{paddingRight:15}} onPress={()=>{}}>
<View style={{flexDirection:'row',alignItems:'center',padding:5,height:36}}>
<Text style={{color:'#9a8f8d',fontSize:13}}>更多</Text>
<Image style={{width:17,height:15,marginLeft:5,resizeMode:'contain'}} source={require('image!finance_more')}/>
</View>
</TouchableWithoutFeedback>
var insurance =
<View>
<TouchableWithoutFeedback onPress={()=>{
this.setState({expanded:!this.state.expanded});
this.props.onExpand&&this.props.onExpand(this.state.expanded);
}}>
<View style={{flexDirection:'row',alignItems:'center',borderColor:'#dddddd',borderTopWidth:0.5,borderBottomWidth:0.5,backgroundColor:'white'}}>
<Image style={{width:6,height:36,resizeMode:'stretch'}} source={require('image!finance_list_bar_current_deposit_retract')}/>
<Text style={{textAlign:'center',fontSize:17,color:'#d78d85',marginLeft:16,}}>保险</Text>
<Text style={{fontSize:13,color:'#9a8f8d',marginLeft:5,flex:1}}>保障每一天</Text>
{!this.state.expanded&&<Image style={{width:10,height:10,resizeMode:'contain',marginRight:15}} source={require('image!common_ic_more_spread_out')}/>}
{this.state.expanded&&moreView}
</View>
</TouchableWithoutFeedback>
{this.state.expanded&&listView}
</View>;
return insurance;
},
});
Avertisement
var Avertisement = React.createClass({
render:function()
{
var advertisement =
<View style={{margin:8,alignItems:'center'}}>
<TouchableHighlight>
<Image style={{resizeMode:'contain',width:344,height:146.7}} source={require('image!finance_banner_001')}/>
</TouchableHighlight>
<TouchableHighlight style={{marginTop:8}}>
<Image style={{resizeMode:'contain',width:344,height:146.7}} source={require('image!finance_banner_002')}/>
</TouchableHighlight>
</View>;
return advertisement;
}
});
整体
var FinanceScreen = React.createClass({
render:function(){
return (
<ScrollView ref={(scrollView)=>{
this.scrollView=scrollView;
}}>
<View style={styles.container}>
<TitleBar loginState={0} title={'未登录'}/>
<Header/>
<Insurance onExpand={(expanded)=>{
}}/>
<Avertisement/>
</View>
</ScrollView>
);
},
});
TabLayout
'use strict'
var React = require('react-native');
var {
Image,
Text,
View,
StyleSheet,
TouchableWithoutFeedback,
TouchableOpacity,
} = React;
var iconHome = [require('image!tab_home_normal'),require('image!tab_home_focused')];
var iconFinance = [require('image!tab_finance_normal'),require('image!tab_finance_focused')];
var iconBank = [require('image!tab_bank_normal'),require('image!tab_bank_focused')];
var iconLife = [require('image!tab_life_normal'),require('image!tab_life_focused')];
var iconCredit = [require('image!tab_credit_normal'),require('image!tab_credit_focused')];
var titleHome = '首页';
var titleFinance = '理财';
var titleBank = '银行';
var titleLife = '生活';
var titleCredit = '信用';
var tabArray = [{icon:iconHome,title:titleHome},{icon:iconBank,title:titleBank},{icon:iconFinance,title:titleFinance},
{icon:iconCredit,title:titleCredit},{icon:iconLife,title:titleLife}];
var TabView = React.createClass({
_handlePress :function(){
if(this.props.onPress)
{
this.props.onPress();
}
},
render:function(){
return (
<TouchableWithoutFeedback onPress={this._handlePress}>
<View style={styles.tabViewContainer} on>
<Image style={styles.tabViewIcon}
source={this.props.selected?this.props.icon[1]:this.props.icon[0]}/>
<Text style={[styles.tabViewText,this.props.selected?styles.tabViewTextFocused:{}]}>{this.props.text}</Text>
</View>
</TouchableWithoutFeedback>
);
},
});
var TabLayout = React.createClass({
select : function(position){
if(this.state.selected!==position){
this.setState({selected:position});
}
},
onTabChanged : function(position){
this.setState({selected:position});
if(this.props.onTabChanged)
{
this.props.onTabChanged(position);
}
},
getInitialState: function(){
return ({
selected:0
});
},
render:function(){
// var tabViews = [];
// for(var i=0;i<tabArray.length;i++)
// {
// var tab = tabArray[i];
// tabViews.push(<TabView icon={tab.icon} text={tab.title} selected={this.state===i} onPress={()=>{
// this.state.selected!==i&&this.onTabChanged(i);
// }}/>);
// }
return (<View style={styles.tabLayout}>
<TabView icon={iconHome} text={titleHome} selected={this.state.selected===0} onPress={()=>{
this.state.selected!==0&&this.onTabChanged(0);
}}/>
<TabView icon={iconBank} text={titleBank} selected={this.state.selected===1} onPress={()=>{
this.state.selected!==1&&this.onTabChanged(1);
}}/>
<TabView icon={iconFinance} text={titleFinance} selected={this.state.selected===2} onPress={()=>{
this.state.selected!==2&&this.onTabChanged(2);
}}/>
<TabView icon={iconCredit} text={titleCredit} selected={this.state.selected===3} onPress={()=>{
this.state.selected!==3&&this.onTabChanged(3);
}}/>
<TabView icon={iconLife} text={titleLife} selected={this.state.selected===4} onPress={()=>{
this.state.selected!==4&&this.onTabChanged(4);
}}/>
</View>);
},
});
var styles = StyleSheet.create({
tabLayout:{
flexDirection:'row',
backgroundColor:'white',
height:56,
borderTopColor:'#e8e8e8',
borderTopWidth:0.5,
borderBottomWidth:0.5,
borderBottomColor:'#e8e8e8',
},
tabViewContainer:{
flex:1,
flexDirection:'column',
alignItems:'center',
justifyContent:'center',
},
tabViewIcon:{
width:30,
height:30,
resizeMode:'contain',
},
tabViewText:{
color:'#9a8e8c',
fontSize:13,
textAlign:'center',
},
tabViewTextFocused:{
color:'#63534e',
}
});
module.exports = TabLayout;